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<h2><a name="SECTION0035140000000000000000"></a><a name="writer-impls"></a>
<br>
33.1.4 Writer Implementations 
</h2>

<p>
Three implementations of the writer object interface are provided as
examples by this module.  Most applications will need to derive new
writer classes from the <tt class="class">NullWriter</tt> class.

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><span class="typelabel">class</span>&nbsp;<tt id='l2h-5545' xml:id='l2h-5545' class="class">NullWriter</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
A writer which only provides the interface definition; no actions are
taken on any methods.  This should be the base class for all writers
which do not need to inherit any implementation methods.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><span class="typelabel">class</span>&nbsp;<tt id='l2h-5546' xml:id='l2h-5546' class="class">AbstractWriter</tt></b>(</nobr></td>
  <td><var></var>)</td></tr></table></dt>
<dd>
A writer which can be used in debugging formatters, but not much
else.  Each method simply announces itself by printing its name and
arguments on standard output.
</dl>

<p>
<dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline">
  <td><nobr><b><span class="typelabel">class</span>&nbsp;<tt id='l2h-5547' xml:id='l2h-5547' class="class">DumbWriter</tt></b>(</nobr></td>
  <td><var></var><big>[</big><var>file</var><big>[</big><var>, maxcol<code> = 72</code></var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt>
<dd>
Simple writer class which writes output on the file object passed in
as <var>file</var> or, if <var>file</var> is omitted, on standard output.  The
output is simply word-wrapped to the number of columns specified by
<var>maxcol</var>.  This class is suitable for reflowing a sequence of
paragraphs.
</dl>

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